The spray freeze drying technology mainly includes two processes, that is, freezing droplets into ice balls and the ice balls drying. Specifically, the two processes may be performed in one apparatus or may be performed in two apparatus separately. Currently, with a laboratory-level small spray freeze drying device, the two processes of freezing and drying can be realized in one device. However, the above method is merely applicable to a small intermittent operation, and not applicable to continuous operation or a large and medium-sized device.
To achieve continuous operations, it is required to transfer the collected ice balls into a vacuum freeze drying device, and a process of transferring the collected ice balls typically has the following three problems.
1. Moisture in the air enters into a freezing chamber, causing freezing on an inner wall of the freezing chamber;
2. The moisture in the air accumulates on a surface of the ice ball, causing the ice balls to be bonded; and
3. The ice balls melt.
Hence, it is necessary to provide a further solution for the above problems.